I need to document calculations including

- the used equation and
- the variables replaced by the values used

Example: A=1, B=2

C=A+B

3=1+2

I am using Reportlab and create flowable elements with matplotlib. The following code based on the help and can achieve No.1 from the list above. Two questions arise:

How can I insert variable values in my

`mathtext_demo`

?Is there a way to write the general equation and the one with substituted values and result using some dictionary/solv

import matplotlib.pylab as plt mathext_demos = (r'$(frac{5 - frac{1}{x}}{4})$') def make_equation(code,fsize=20,imgheight=70): fig=plt.figure(figsize=(7, 0.1)) plt.annotate(code, xy=(.4, 0.1), ha='center', fontsize=fsize) plt.axis('off') make_equation(mathext_demos)

## Answer

- You can use variables in your string:

a = 5 b = 4 mathext_demos = (r'$(frac{%s - frac{1}{x}}{%s})$' %(str(a), str(b)))

You can also use `%f`

for float, but I think that is something you have to figure out what works for you.

- You can write a function with the arguments
`a`

and`b`

for example en return the string. Is that what you meant with your second question?

def create_mathtext(a,b): c = a + b return r'${%s} = {%s} + {%s}$' % tuple(map(str, [c, a, b])) make_equation( create_mathtext(1, 2))